The format[datetime] parameter

With the format[datetime] query parameter you can specify a datetime output format of unix/timestamp or iso-8601/json. The unix and timestamp fields are synonymous and output datetimes as UNIX time stamps (i.e. seconds from epoch). The other options - json and iso-8601 - are also synonymous and will output all datetimes as the human readable ECMA-262 format: YYYY-MM-DDTHH:MM:ss.

Please note that right now we output ECMA-262 datetimes implicitly in the UTC timezone.